In the production of rubber or rubber-like weatherstrips of the type commonly used on motor vehicles around the doors, windows and trunk covers, it is common to reinforce each weatherstrip with a formed metal element which is continuously fed through an extruder head having a die for forming the weatherstrip with the desired cross-sectional configuration. One type of continuous reinforcing strip which has been used is in the form of a serpentine-shaped continuous wire to which is stitched longitudinally extending thread-like filaments.
Another form of metal reinforcing strip is disclosed in U.S. Pat. No. 2,290,842 wherein a flat strip of sheet metal is fed between a pair of driven cutting and forming rolls 26 and 27 (FIG. 5) which slit the strip, as shown in FIGS. 2 or 7. The slit strip is then fed around a higher speed drum 39 against which the strip is held by a pressure roll 40. The higher peripheral speed of the drum 39 is used to stretch the slit strip to an expanded strip, as shown in FIGS. 3 and 8. The edge portions of the expanded strip are then rolled around longitudinally extending wires 3, which limit further stretching of the strip. The strip is bent along the fold lines 10 and 11 to form either of the channel-shaped expanded metal reinforcing strips shown in FIGS. 1 and 6.
Other forms of expanded metal reinforcing strips are produced by slitting a metal strip with laterally extending slits and then coining or thinning a longitudinally extending portion or portions of the strip. This method is used to form a ladder-like expanded metal strip, such as disclosed in British Patent Application No. 2,067,105 or Japanese Patent Application No. 60-156766, or a fishbone-type expanded metal strip. In the latter strip, parallel spaced pics or wings project laterally outwardly from opposite sides of a center spline portion which is coined or reduced in thickness to produce the space between the wings.
It has been determined that the cutting and expanding apparatus disclosed in FIG. 5 of U.S. Pat. No. 2,290,842 does not produce uniform and precision expansion of the cut sheet metal strip. It has also been found undesirable to feed a non-uniformly expanded strip into an extrusion head, and a rubber-like weatherstrip with a non-uniform reinforcing insert is undesirable. Furthermore, the operation of attaching the wires 3 is relatively slow and expensive. Problems are also encountered with the fishbone-type expanded strip in that the laterally projecting and longitudinally spaced wings are easily bent in a longitudinal direction when the strip is being fed through a rubber extruder head. This results in an undesirable or unacceptable weatherstrip product which is not uniformally reinforced along its length.